This invention relates generally to a security device for removably locking two mobile elements together. The security device is intended for fixing to one of the two elements, and includes an engagement member arranged to move from a position of engagement to a position of disengagement and vice versa, control means for the engagement member, and one or more elements for transmitting the operation of the control means to the engagement member.
More particularly, the present invention relates to a lock for closing and locking doors and the like, the lock being of the type which can be adapted to different keys. More specifically, the lock can be arranged to operate either with one or more keys, it being possible to replace each key independently of the others.
Certain existing locks comprise an arrangement of two opposing components, each of which is compelled by the action of a key to assume a variable position relative to the other. There is also a known lock comprising a group of transmission elements intended for operation by a key. Each transmission element of the group is pivoted, and operates a single abutment element to allow the movement of a bolt. However, this lock has the disadvantage of being able to be adapted to only one key at a time. This means that it is impossible for the lock to be able to be operated by two different keys, for example a change key and a master key.
There are also known locks which although not adaptable to different keys, comprise two groups of transmission elements which also perform the function of control elements. However, the control elements are intended to simultaneously allow the movement of the bolt.
Locks known as one or more level master key locks are also available commercially, these being operable by one or more master keys according to the number of levels, and by one change key. In these locks, the keys preset one or all the consent arrangements or combinations which govern the locking and release of the bolt.
Known multiple-level locks generally have the disadvantages that it is not possible to replace any one of the master keys of the change key without replacing at least a large part of the control mechanisms. This can give rise to serious drawbacks if it becomes necessary to make a master or change key inoperable, for example, in the case of loss, withdrawal or copying of a key.